Update FloatingIconView to display PreloadIconDrawables during swipe home animations.

Swiping up to go home on an app that is downloading incrementally would cause a jittery animation. Updated FloatingIconView to animate directly to a PreloadIconDrawable.

Demo: https://drive.google.com/file/d/1ddr8OGR4c1ZneyQ0VkkAAxGpwNcP8Wyn/view?usp=sharing

Fixes: 177685929

Test: manual
Change-Id: I4cd2daa18f6d3fed42a9b666063e0b1c1c46e5d9